Mass storage devices are tested during production to determine the quality and/or reliability of the device. The testing is also called a certification process. To test the device, certification firmware is downloaded to a read-only-memory (ROM) of the mass storage device and executed. The certification firmware includes a number of certification tests. During the certification process, the certification tests are executed on a mass storage device in a predetermined sequence of the tests until the entire sequence of certification tests is completed or halted. The sequence of certification tests will halt when the any one of the tests in the sequence fails. The certification tests are then downloaded with customer firmware in preparation to be shipped to a customer.
One of the certification tests is a test of the bit error rate (BER) of the mass storage device. The BER is an indication the quality and/or reliability of the device during testing for acceptance or failure rejection. The BER is also used for tuning a read channel of the mass storage device. However, BER determination is a slow process that increases the cost of testing and tuning a mass storage device.
In another conventional solution to testing and tuning a mass storage device, the time domain equalized signal-to-noise ratio (ESNR) is determined. The ESNR is determined by computer-readable logic that is implemented outside of the mass storage device. The ESNR test logic is not stored on, or downloaded to memory of the mass storage device. In one example, the logic is implemented in software on a computer that is operably coupled to the mass storage device through a communication channel or link. The logic is executed after retrieving the respective data from the mass storage device. However, the communication channel or link between the device that implements the ESNR logic and the mass storage device is slow. The slow link has the effect of greatly increasing the time to transfer mass storage data that is input to the ESNR logic.
Furthermore, conventional methods of determining ESNR include phase level retry or global level retry. Phase level retrying includes subsequent attempts to verify or and/or qualify one or more read phases of data that previously failed to verify or and/or qualify. Global level retrying includes subsequent attempts to read the one or more phrases of data after the phases are determined to have an unacceptable ESNR. The mutually exclusive use of phase level retry and global level retry reduces the accuracy of the determined ESNR value.
What is needed is a system, method and/or apparatus improves the speed of determining the ESNR value of a mass storage device. A system, method and/or apparatus that improves the accuracy of the determined ESNR value is also needed.